This invention relates to relay contacts in general and more particularly to the use of a sintered material which consists of 50 to 85% nickel and 50 to 15% cobalt, as a material for electric relay contacts.
A small degree of material migration is a requirement for relay contact materials because the switching operation can be disturbed by the development of hills and valleys resulting in failure of the relays. A further requirement is low contact resistance. In contact materials containing silver, sulfide layers cause an unfavorable increase of the contact resistance values. For this reason, palladium alloys have been used which form substantially less sulfide film on the contact surface and therefore have lower, more favorable contact resistance. This, however, involves contact materials rich in rare metals.
It is thus, an object of the present invention to find a sintered material with a low rare metal content for use as the contact material for electric relay contacts of the nickel-cobalt type which exhibits great hardness and practically no increase of the contact resistance and practically no material migration under current load.